


defuse your private bomb

by spikeymarshmallows



Series: look at me when i hurt you [5]
Category: The Umbrella Academy (TV)
Genre: Dom/sub Undertones, Established Relationship, Knifeplay, M/M, Plot What Plot/Porn Without Plot, Porn with Feelings, Pseudo-Incest, Service Top Diego Hargreeves, light bloodplay
Language: English
Status: Completed
Published: 2020-01-08
Updated: 2020-01-08
Packaged: 2021-02-18 22:27:39
Rating: Explicit
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 8,352
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22167496
Author URL: https://archiveofourown.org/users/spikeymarshmallows/pseuds/spikeymarshmallows
Summary: "Hurt me? Hurt me… Bad. Worse than we usually do. I-," He paused, visibly clenching his jaw as he, for once, seemed to struggle with his words. "I don't know how just… Whatever you're thinking, but more than that. And then more than that again. Just… hurt me. Please." His voice was so small, almost pleading.Klaus' eyes kept darting around the room as if the small space had the answer. Diego watched. Several times, Klaus' eyes landed on some of the knives that hung on the wall."Okay," Diego said slowly. "I have an idea."*Featuring surprisingly feels-y knifeplay
Relationships: Diego Hargreeves/Klaus Hargreeves
Series: look at me when i hurt you [5]
Series URL: https://archiveofourown.org/series/1595641
Comments: 16
Kudos: 183





	defuse your private bomb

**Author's Note:**

> This is not a how-to guide on how to do knife play! For starters, you should prepare the area... Also, I'm not a knife play expert (but I dabble in other medical play) so…. seriously. Not a "how to knife play"! 
> 
> But this is.... softer knifeplay (or at least has more feels) than one might expect.
> 
> Thank you to my favourite [emptydistractions](https://archiveofourown.org/users/emptydistractions/pseuds/emptydistractions) for the beta again!

Klaus had been fidgeting all day. Diego didn't quite know how to describe it, but he was bouncing his legs a lot more than usual, tapping his fingers over and over on any available surface, shifting his weight every few minutes. And he wasn't saying anything. That, in and of itself, spoke volumes.

He'd walked around the room a number of times, heading out into the gym, pacing frenetically. If Diego didn't know better, if this was the Diego of even a few months ago, he'd have assumed Klaus was high. But Diego had learned that a high Klaus tended to be a lot more chill, and it was only when the drugs wore off that he went back to his manic energy. Klaus, apparently, hadn't touched coke in years, not since he'd broken a tooth at 23 from clenching and grinding his teeth. Instead his drugs of choice had been benzos, E, ketamine, and of course, his weight in weed and alcohol.

Diego was torn between wanting to snap at him and asking what the fuck was wrong, or bringing him in for a hug in the hopes that it might soothe whatever it was that had gotten under Klaus' skin.

"I'm going for a walk," Klaus eventually huffed, getting to his feet and brushing invisible dust off of the thin cotton dress he'd chosen for the day.

This was one of those times that Diego was conflicted. He wasn't Klaus' babysitter, but he was Klaus'... something. Something more than a brother, at least. And Klaus had been sober and clean for 73 days (and they  _ were _ counting) now, and the physical withdrawal had passed. But that didn't mean that the emotional addiction was gone. And it didn't mean that Diego didn't want to support him. 

"It's raining," Diego pointed out flatly, glancing at the windows.

"I know," Klaus huffed, pulling on his patchwork coat and boots.

Diego pursed his lips and removed the glasses he only wore for reading (and even then, rarely), rubbing at the bridge of his nose. "Do you want company?" It felt like a good compromise. He wouldn't be making Klaus feel watched every second of the day, but if Klaus needed the support hopefully he'd see Diego's offer for what it was.

Klaus frowned, pressing his lips together into a thin line. "Are you just going to follow 100 feet behind me the whole way?"

Well, Diego hadn't planned on it, but he could see where Klaus was coming from. He _had_ done so before, and he wasn't above doing it again. And this time he wouldn't get caught.

"Depends," Diego mused, chewing on the temple tips of his glasses. "Are you doing anything I _should_ follow you for?"

Klaus' frown deepened in contemplation. "No. I just want to walk in the rain like the heartbroken heroine in a romantic comedy"

" _Are_ you the heartbroken heroine in a romantic comedy? Is there something I should know here?"

Klaus rolled his eyes, resting his arms on the metal railing beside Diego's door as he began to roll himself a cigarette that would no doubt fizzle out in the rain outside.

"Leave the jokes to me, Diego," Klaus said flatly. Even from the couch, Diego could see that there was a small smile tugging at the corners of Klaus' mouth. Diego pushed himself up off of the sunken couch, the ground cold under his bare feet. He climbed up one of the stairs, putting himself just a step below Klaus.

"In all seriousness… Should I be worried?" Diego asked quietly.

Klaus sighed, looking up at the ceiling as if it might provide answers, unlit cigarette held loosely between his lips. Finally, he looked down and draped two long arms around Diego's shoulders. "No."

"I can come with you if you want. Or I can follow, if you're into that." Diego winked to show that he was joking. "But it's been seventy-three days, and I've got to let you out on your own sometimes."

Klaus gave him a tight smile. "Yeah, I know."

Diego stood on his tiptoes to give him a small kiss, the stairs making Klaus that much taller than him.

"But if you need the support, just tell me," Diego continued, pulling back as he brought his hands up to rest on Klaus' hips. "You're allowed to ask for that."

Klaus seemed to ponder this as he tucked his first cigarette away and began rolling another. Diego liked to see it. Klaus wasn't just blindly saying what Klaus could and couldn't do, as he might once have done. That he was taking the time to think about it meant that Diego could, hopefully, trust him. And if he relapsed? Well, he relapsed and they'd deal with it if it came to that. It wouldn't be the first time it had happened since the almost-apocalypse, since the start of… whatever this was between the two of them.

"No," Klaus said finally, tucking the second cigarette into his pocket. "No, it's okay. I'm not going to do anything stupid. Just need to clear my head."

"As the heroine in a romantic comedy?"

Klaus leaned down to give him another kiss before withdrawing. "Paul Rudd's got nothing on you, baby."

Diego grinned. "Okay, but if you're not back in an hour, I will come looking for you. Is it a romantic comedy if I don't save the day?"

"Clearly you need to watch more romantic comedies," Klaus huffed at the door, showing Diego his _Good_ _Bye_ even though using his other hand would have been easier.

Diego waited a few breaths before he sat back down, tucking his feet under him to warm them up. It would be fine. This was necessary. Much as he'd like to, he couldn't be Klaus' shadow. He could only hope that Ben would be able to stop Klaus if he looked like he was about to surrender to any urges. He 100% did not think about the fact that Ben had been around Klaus all the time and Klaus had still had countless relapses.

He sighed and went back to his book. His eyes hurt a little, but now that Klaus was gone he wasn't going to wear the stupid glasses. The only reason he wore them at all was because if Klaus was on the road to self-improvement, the least Diego could do was wear his reading glasses. But if Klaus wasn't here… He frowned to himself. If Klaus only did good things when Diego was around, Diego would be disappointed. With a sigh, he shoved the stupid black frames back onto his face, hating that his foundling headache abated with the visual assistance.

Self-improvement was a fuckin' joke.

*

By Diego's measure, Klaus wouldn't be home for a while yet. He'd gotten a few more pages into his book before he'd started to get fidgety himself. He'd already worked out (twice) that day and it would put unnecessary strain on his body to train any further. Diego knew himself well enough to know that he was only one bad mood away from overtraining anyway.

Instead, he checked the bar fridge in the corner of the room. He needed a few more supplies if he and Klaus wanted to eat that night. It would just be omelettes again; they were the easiest thing to cook in the little space other than a simple stir fry. Maybe they could look at getting a bigger place. No, no, he was getting ahead of himself. Klaus had been crashing at Diego's place (in his bed) for barely six months. Sure, the space was a little cramped at times. Sure, Diego probably needed a new place anyway, and could afford it now that his inheritance had come through. But it felt strange to think that he might get a place _with Klaus_. And yet, the idea of getting a place without Klaus felt unfathomable.

Still. Place or no place, it didn't solve the problem of dinner that night. He probably had enough time to run to the corner store and back before Klaus returned. He wanted to be home when Klaus got back; he didn't want Klaus to think he'd actually tailed him. He wanted Klaus to know that Diego trusted him, even when it scared him to do so.

It was bucketing down outside, utterly miserable and chilly with the impending fall. He hoped Klaus was warm enough because he was a downright miserable bastard when he was cold.

He had just finished putting the few groceries away when the door swung open and a drenched Klaus squelched back in.

Klaus didn't look all that much better for his walk. His lips looked faintly blue and his eyes, instead of manic, simply looked miserable. Diego stopped what he was doing to go up to him, resisting the urge to pull Klaus into his arms. Diego didn't mean to coddle, but it was something that came out in him more and more when Klaus was involved. Instead of drawing Klaus in for a hug, he rested both of his hands on Klaus' shoulders.

"Klaus." He kept his voice even but didn't try to hide his concern. He hadn't seen Klaus this downtrodden in months. "You okay?"

"Yeah," Klaus said, sounding dangerously close to a whine. "Turns out walking in the rain is less dramatic and poetic and mostly just pathetic and cold."

Diego couldn't stop a small smile from crossing his face. "I admit, you look more like a drowned raccoon than any heroine that I've ever seen."

"I feel like a drowned raccoon," Klaus sighed dramatically.

Diego gave him a once over. "You didn't even take your umbrella?"

"It ruined the mental image I had in mind! How was I supposed to look suitably dramatic in my monsoon walk with an umbrella?"

"Jesus, Klaus." He was torn between thinking Klaus was an idiot and thinking he was adorable. Honestly, most of the time Diego settled on thinking that Klaus was an adorable idiot; two birds, one stone, etc.

"Go shower. I'll cook you something to eat, okay?" Diego said, kissing him on the cheek. His skin freezing cold against Diego's lips, and he was surprised that Klaus' teeth weren't chattering more. He hoped the showers were relatively empty. That was another reason to consider another place. Diego was starting to get sick of sharing his bathroom with whoever used the gym, and it was particularly inconvenient given Klaus' love of shower sex.

He set about making them omelettes, going hard on the cheese for Klaus', and using more vegetables and egg whites in his own. Klaus may not have been at the stage where he was treating his body as a temple, but at least Diego had discovered the best way to get vegetables and protein into him was through concealing them in copious amounts of cheese. Diego knew how to pick his battles.

Diego had just finished with Klaus' omelette when Klaus clattered in from his shower, looking moderately better than before. Not for the first time, Diego wished they had access to a bath that didn't involve going back to the Academy. Baths often seemed to cheer Klaus up.

Klaus dropped his sodden dress in the corner, hung his wet coat behind the door, and came up behind Diego. He was wearing what had to be one of Diego's shirts given that it was a touch looser on him than Klaus' own usual clothing, yoga pants, and a long drapey sweater that hung around his thighs. He wrapped his arms around Diego's middle, tucking his head into the space between Diego's shoulder and neck.

"Smells good," he mumbled against Diego's skin. Klaus felt a little warmer now, his hands less frigid when Diego squeezed them before going back to carefully preparing his own food.

"Yours is there." Diego nodded at the dish to the side. "It's still hot."

"Thanks, Diego." It seemed to take Klaus an immeasurable amount of strength to push himself away from the touch, but he managed.

The room was silent except for the soft sizzle of the omelette and the patter of rain outside. Just as Diego's omelette was nearly done, he broke the silence: "Wanna talk about it?"

Klaus sighed. "No," he said, sounding dangerously close to a whine. When Diego glanced at him, Klaus was picking at his food with his fork. Diego said nothing, trying not to go for his usual demands that Klaus open up.

He took his food to the couch and sat down beside Klaus. Despite his morose expression, Klaus inched closer and tucked his bare feet under Diego's thigh. He barely seemed aware that he was doing it, the action seemingly instinctive by now.

"You're not eating," Diego pointed out.

Klaus blinked a few times, zoning back into reality. "Yeah, I know… Sorry." He twirled the food with his fork, bringing a morsel up to his mouth.

There were some battles Diego fought, others he didn't. Food was touch and go. Klaus seemed to struggle with appetite often; some days he was so hungry that nothing seemed to touch it while others he was barely able to get down a few bites. Diego was tempted to fight him on it tonight. Fortunately, it seemed now that Diego was beside him and had mentioned Klaus' lack of intake, he was increasing the pace at which he picked. That was good enough.

"Do you ever have days where just… everything feels wrong, like your skin is on the wrong body, and everything in the room isn't quite in its right place, even though you know that it is? Unless… Did you shift everything in the room just a little bit? Because if you did, it would be confusing, but at least it would explain things."

Diego fixed Klaus with a look that he hoped accurately portrayed just how insane he thought Klaus sounded. "No, Klaus, I did not shift everything in the room just a few inches for the sole purpose of fucking with you," he said flatly.

"Oh, I didn't say it was to fuck with me. Or that it was a few inches. Oddly specific. _Did_ you?"

Diego sighed, putting his fork down. "No, I didn't."

"Oh."

There was a beat. Silence.

"Do you ever get that feeling though?"

"No," Diego said almost instantly. But that wasn't entirely true. He might not have used the words that Klaus had, but there were certainly days that he ran until he couldn't breathe, punched until his knuckles were bruised and splitting, trained until all he could think about was the burning in his body. Thinking about it that way, Diego wasn't entirely sure his coping mechanisms were all that much healthier than Klaus'.

He exhaled steadily, setting his half-eaten dinner aside so that he could give Klaus his full attention. He took Klaus' plate, put it beside his own and turned so that he was facing Klaus fully, grabbing Klaus' long, thin fingers with one of his hands.

"What do you need me to do?" Diego asked softly, gripping Klaus' chin so that he could force him to meet his eyes. Klaus resisted the eye contact for a moment, eyes darting between meeting Diego's and looking anywhere but. He gave in quickly though, seemingly not even having enough fight in him to resist that right now. Miserable eyes met Diego's own.

Klaus licked at chapped lips before he finally said, "Hurt me?"

Was that it? Diego did that as often as he could, may as well have done it for three meals a day, plus snacks. There had to be something more to it. He didn't say anything, waiting to see if Klaus volunteered more information.

It was worth it when Klaus licked his lips again and exhaled shakily before saying, "Hurt me… Bad. Worse than we usually do. I-," He paused, visibly clenching his jaw as he, for once, seemed to struggle with his words. "I don't know how just… Whatever you're thinking, but more than that. And then more than that again. Just… hurt me. Please." His voice was so small, almost pleading.

It was Diego's turn to exhale shakily now. He wasn't sure what Klaus was quite implying, or how much harder he actually meant. They weren't strangers to rough sex, but Diego wasn't sure how much more Klaus wanted and, more to the point, how much more Diego could provide. He kept watching Klaus, hoping the answers might somehow reveal themselves.

Klaus' eyes kept darting around the room as if the small space had the answer. Diego watched. Several times, Klaus' eyes landed on some of the knives that hung on the wall.

It gave Diego an idea. Would that be okay? Was that something Diego could be okay with giving him?

"Okay," Diego said slowly. "I have an idea."

*

Diego set the ground rules, which seemed in direct contrast to what was actually the right thing to do. He'd done his research and he knew that the power lay with the person getting hurt most of the time. But Diego didn't trust Klaus to know his own limits yet; and even if he knew them, _Diego_ had limits to what even he would do.

It wasn't that the sex they had was gentle, not at all. Klaus was no stranger to Diego's belt, to Diego's hand across his backside or his face. He was familiar with Diego's fingers in his mouth and in his hair. Diego couldn't remember the last time Klaus had come without Diego's hand at his throat. But this seemed like a pretty big step up in terms of brutality. And Diego had been the idiot who had suggested it.

Diego wasn't vanilla by any means, but Klaus had a way of pushing for more intensity, always more, and Diego wasn't always comfortable delivering. He didn't mind hurting Klaus; he actively loved hurting Klaus, making him a writhing, sobbing mess on his bed. What Diego never wanted to do was harm Klaus, and sometimes he feared (knew) that Klaus didn't have the same standards.

So Diego laid out the rules. Klaus wasn't allowed to move when Diego had his knives out. He could make as much noise as he wanted, he could beg and plead, but he wasn't allowed to move just in case Diego's reflexes weren't quick enough to prevent a true injury. There would be no safe words; if Klaus said 'no' or so much as shook his head, the scene would be over. And when they were done, Klaus had to accept as much care as Diego wanted to give him.

Klaus agreed, pulling a face at the final condition. But hey, however awkward Klaus still was about accepting aftercare, he accepted it nonetheless.

And that was how Diego ended up with a faintly trembling, naked Klaus kneeling at his feet.

"You look good like this," Diego commented, far more casually than he felt.

Klaus gave him a weak smile. "You always say that."

"You always look good like this." Diego grinned. "The only place I think you look better than on your knees is when you're spread out underneath me."

Even Klaus couldn't resist smirking at that.

"But then again, maybe I'm just biased."

Diego tried not to make a big show of easing one of his favourite knives from its leather covering, but even the act of drawing it out slowly felt like he was making a big deal of it. Klaus watched it carefully, eyes widening. Diego adjusted his grip on the knife without a second thought, getting it comfortable in his hand. He sank to his knees in front of Klaus and brought his free hand to the back of Klaus' neck, rubbing his thumb gently over the soft skin there. Quickly, he gripped the hair at the back of Klaus' head and pulled back. Klaus whined, biting his lip.

He came in nice and close to Klaus' face and bit at his jaw. Klaus shuddered. And then Diego drew the knife up to his neck, making sure that Klaus could see it coming. Klaus clenched his eyes shut, breathing a little harder, almost as if he were scared. With Diego's knee between Klaus' legs, he could feel Klaus getting hard. He dragged the knife across the delicate skin of Klaus' neck, being very careful not to break skin, instead scraping the edge so that Klaus would be able to feel the threat of the sharpness without risking anything that Diego wasn't game enough to risk yet. Maybe next time.

He was already thinking about next time.

Diego knew hundreds of ways to hurt a person with his knives, but he'd never used his weapons like this. For perhaps one of the first times in his life, he felt grateful for the years his father had beaten his craft into him. Now, it gave him the knowledge to do this safely, to take Klaus to an edge he desperately needed without risking actual harm.

Klaus whimpered again as Diego pressed down a little harder.

When Diego caught a glimpse of Klaus' expression next, it was already blissed out. He'd barely done more than scrape his knife over Klaus' neck and he already seemed like he'd sunk down to the soft place he sometimes found when Diego was particularly rough with him.

Diego eased back and drew himself up so that he was sitting on the edge of the bed again. He left Klaus on the floor.

"Don't move," Diego breathed against Klaus' ear, not letting go of his hair.

Klaus whimpered again and opened his eyes to look at Diego. Klaus looked beautiful like this.

Diego released the grip on his hair, letting his touch ease until it simply rested there. He felt goosebumps break out over Klaus' skin. Slowly, ever so slowly, Diego dragged the razor sharp edge of the knife along Klaus' collarbone, inch after gentle inch. Klaus exhaled shakily. For someone who was usually incredibly vocal in bed, Klaus was remarkably silent and still.

Diego watched with morbid fascination as the blood bloomed quickly from the shallow cut. He waited for a few moments, checking for any signs of a bad reaction from Klaus. When none came, he did the same again; an identical line an eighth of an inch below the first and just as long. Klaus released a tiny sound again, halfway between pain and enjoyment.

"Do it again," Klaus whispered into the silence when Diego drew his blade away after the third line.

Diego sat back just a little, taking everything about Klaus in. The blood was beginning to dribble down his chest, not heavily but enough. Klaus was still trembling faintly and his face still had that terrifying combination of pleasure and pain. His eyes were lidded and hazy, and he kept biting his lip, taking in shaky breaths. And christ, he was as hard as Diego had ever seen him. His dick was already showing precome at the head, twitching and flushed.

Seeing nothing worth worrying about and hearing Klaus' request for more, Diego turned his attention to Klaus' other side. He drew the blade across Klaus' other collarbone, mirroring the other three cuts he'd made.

"Fuck," Klaus breathed, staring up at Diego as if he had hung the moon.

Diego couldn't help but lean forward to kiss Klaus, cupping his face. Klaus shook and released a breathy moan. Diego allowed himself to relax minutely. Okay. This was okay. Klaus wasn't crying. He didn't seem to be reacting badly. He seemed to be actively enjoying it.

And Diego?

Diego had just realised how hard he was. So focused on Klaus, on hurting him just right, he hadn't noticed his body's reaction to things. A part of him was a little shocked at how strongly he was reacting; this kind of play was something they'd never done, and he still wasn't sure how much he was actually enjoying it. But he did know that he liked hurting Klaus, and that more than anything, he got off on Klaus' enjoyment.

He shifted a little, subtly trying to get more comfortable so that Klaus wouldn't see how hard he was under his black jeans. The movement was enough to draw Klaus' attention though. His eyes flicked from Diego's face to between his legs. Klaus made no effort to hide that he was staring and even licked his lips. Damn if that didn't make Diego's dick twitch again, even just having the reminder of Klaus' mouth.

Klaus gave him a little smirk despite how distant he was beginning to look. Klaus sucked his own lower lip between his teeth before releasing it and sitting back on his heels.

"More?" Klaus breathed.

"Yeah," Diego croaked, adjusting his knife in hand again. He dragged the blade several times below his earlier cuts, enjoying the way the blade caught the earlier drops.

"You have," Klaus panted weakly, "no idea how hard it is not to push harder against that."

"Well, I'm proud of you for being a good boy and not moving," Diego said smoothly, rather than scolding him for an act that Klaus hadn't committed (yet). At that, Klaus melted, the sweetest little smile crossing his face. That had always been always Klaus' biggest weakness; being called 'good boy', being told that he was 'good' seemed to soften him, giving him the praise that they both yearned for.

"Diego," Klaus whined again, squirming. Now that the knife was well out of harm's way, Klaus reached down to touch his own dick, jerking it with a shaky exhale.

"Uh, uh," Diego tutted, bringing the knife up again. "Didn't say you could do that."

Klaus pouted. "But-,"

"You can either have that," he nodded at where Klaus was gripping himself, "or this." He nodded at the knife.

With a battle waging on his face, Klaus finally let go of his dick and let his hands fall back to his sides.

Diego kissed him again softly. "Good boy."

He withdrew, admiring his handiwork for a long moment. Klaus looked good. God, Diego wanted to do it more. And more. And more. He wasn't sure what it was either, because it wasn't the blood. He'd seen blood a thousand times before. It was nothing new, nothing special. He'd seen Klaus bleed, possibly too often, and Diego would go so far as to say he actively didn't like seeing that. But this? This was something else.

Whatever, he'd figure it out later.

Diego pressed his free hand against his crotch, trying to relieve some of the pressure before he turned his attention back to Klaus. Klaus was watching him intently and smiled dopily when Diego leaned forward again.

Diego kissed Klaus deeply, enjoying the way Klaus melted against him. Still kissing him, he dragged the knife down Klaus' right arm with aching slowness. He felt Klaus gasp softly and stiffen at the pain, relaxing the longer the cut went on. Diego loved hurting hurt Klaus and _feeling_ his reactions as much as he loved seeing them.

His relationship with hurting Klaus was complex, and hurt his head to think about too much. Klaus had been through so much and Diego hated adding to that. He, dare he say it, loved Klaus so much that it sometimes kept him up at night, though he was still too cautious to say the words. Hurting Klaus seemed to be in direct contradiction with how he felt; why would he want to hurt someone he loved? But Klaus? Klaus loved being hurt. Diego wasn't sure it always came from a healthy place, particularly in cases such as this. But goddamnit, Diego was an idiot when it came to Klaus, and he was willing to do a lot of things to bring a smile to the other idiot's face.

And then there was the matter of how much it effected Diego. Even if Diego wasn't always sure about giving Klaus the pain he desperately desired. Diego had never been one to question whether something was overtly morally wrong or right. As far as he was concerned, as long as he and Klaus consented they could do whatever the fuck they wanted.

And Diego had never been a stranger to different kinks. He and Eudora had played around. Diego _liked_ leather (and Klaus, plus a leather skirt? Or even those damn leather pants? Possibly Diego's Achilles heel). He _liked_ rough sex. But what he did with Klaus was on another level. And what confused (and aroused) Diego was how much he liked it. He didn't mind it so much as it perplexed him how he'd gone for so long without realising just how much he liked it.

Without looking at the first mark, Diego made another shallow cut along Klaus' arm. Klaus was panting against Diego's mouth and trembling, either from the adrenaline, or fighting the urge to squirm, or both.

Diego felt a line of sweat run down his back. He hadn't even noticed he was sweating, and was glad that he was able to suppress his own shaking.

_This shouldn't feel so good_ , he thought to himself. He drew away from Klaus' mouth and the sound Klaus released was more pained than it had been at any of the cuts.

"Shhh," Diego breathed. "Still here, baby boy." Diego felt weird about calling Klaus his usual nickname; it was such a soft and sweet name for a moment that was supposed to be so brutal.

Klaus dragged his eyes open with obvious effort, mouth hanging open as he panted. He smiled so fucking sweetly at the nickname that Diego wondered why he'd ever thought he couldn't call Klaus 'baby boy' in a situation like this. A wave of fondness and love swamped him so thoroughly that it took his breath away.

Diego studied him, taking it all in: the faint sheen of sweat that made Klaus' skin glow, the glassy look in his green eyes, so stark against the faded eyeliner, the fullness of his mouth, red from where he'd bitten it. And the blood, so vibrant against his skin. As he ran his eyes across Klaus' skin, Diego realised that there was some blood on his fingertips, part of it already dried. Without a second thought, he ran his fingers through some of the lines of blood that had begun to run down Klaus' arms. He was careful not to touch the cuts themselves, not wanting to introduce anything into them that could lead to infection. But the blood itself, the evidence that Klaus trusted him enough to do this to him? Fuck.

He was throbbing in his jeans now, uncomfortably hard. When he glanced down, Klaus seemed to be in a similar state. Precome had dripped down the head of his dick, and it looked just as painful as Diego felt.

Again, he leant in for a kiss. Without drawing away from Klaus' mouth, he shifted forward on the bed, wanting to bring Klaus even closer to him. Klaus brought his arms up and around Diego's waist, rocking back and forth on his heels as he thrust into the air as if that could provide him any relief.

"How're you doing?" Diego asked against his mouth. "Want more?"

Klaus' nod left no space for argument, and as far as Diego could tell, he was still cognisant enough to make choices. He stilled his movements when Diego drew away again, hissing at the next few slices made through the skin of his arm.

Diego's heart raced and his dick throbbed. It felt like the world was moving faster, faster, faster. He wanted to hurt, wanted to make Klaus make that face again, that sound again. God, he looked good. It felt good. The adrenaline was well and truly surging through Diego now, and he just wanted to mark Klaus up so pretty and-.

He took a few steadying breaths, trying to keep himself firmly in reality. It hadn't occurred to him how much _he_ might enjoy this, that he might get caught up in the surge of power that was wrapping itself around him.

His thumb swiped through the blood on Klaus' arm, and god, he wanted to _taste_ it. It was only at the last moment that he remembered he hated the taste of blood. He was more than familiar with the metallic tang, and that because it was Klaus' didn't mean it would actually taste any better.

Diego's shallow breathing matched Klaus'.

Their eyes met again.

The moment stretched out, the world narrowing down to Klaus' pretty face and the heat coursing through his own body.

And then he was tugging Klaus up into his lap as Klaus scrambled to get as close as possible. He pulled Klaus into a kiss that was more teeth and tongue than anything else, carefully burying the hand that held the knife in Klaus' hair; he'd wash the blood out later. Klaus ground against him, rubbing himself off on whatever parts of Diego he could reach. Diego pulled him down closer so he could thrust up against Klaus as well, muffling a groan against Klaus' lips.

He pulled back, pushing Klaus away only as much as he needed in order to unbuckle and unzip his jeans. Klaus was nodding furiously, for once apparently at a total loss of words, as Diego brought him back in.

They ground against each other like teenagers, neither able or willing to stop kissing or moving long enough to get themselves into a better position for more contact. Klaus was all but bouncing on him like he was trying to ride Diego and, fuck, wasn't that a good idea.

"H-hold on, hold on, baby," Diego breathed as he struggled to lean over, trying to find the lube generally tossed beside the bed. He managed to reach it and sat back up, his shaking hands fumbling to get some lube on his fingers. Klaus seemed agreeable with this course of events, moaning desperately as Diego sank two fingers inside of him. Klaus basically did the prep work himself, riding Diego's fingers and pressing his cock to the front of Diego's sweatshirt, no doubt smearing precome across the black fabric. Diego didn't give a shit. Diego withdrew his fingers, and Klaus didn't even whine; he knew what was coming next. Instead, he breathed a litany of affirmations, telling Diego to hurry the fuck up as Diego drew his cock out and gave himself a cursory twice over with lube. Klaus could take him with little to no prep these days, despite his size, and fuck if that wasn't a turn on and a half.

They both groaned when Klaus sank down on Diego's cock. Klaus stilled only for a few seconds, letting himself simply enjoy the sensation of having Diego inside of him again (as if Diego hadn't fucked him silly last night). Diego didn't mind the pause, both hands grasping at Klaus' thighs, smearing blood on one and lube on the other.

Klaus began to fuck himself on Diego's cock, not bothering to muffle his sounds against Diego's skin. Diego yanked him down with a hand in his hair, dragging him close so that he could bite Klaus' lip. The heady, desperately horny part of him wanted to split the skin with his teeth, but the rational part of him knew that there was nothing sexy about having a split lip, and that Klaus would bitch him out if he dared do such a thing.

Klaus felt so good around him, against him, his hands grasping Diego's shoulders for leverage as he drove them both mad. Klaus was incoherent; the only sounds that escaped his mouth were garbled curses and desperate sounds for more, more, more.

And fuck if Diego didn't want to give him more.

With that thought driving him, he pulled Klaus off of him, no time or space for gentleness. Klaus didn't even protest; given how often he professed his love of Diego throwing him around, Diego supposed he knew why. He dropped the knife on the bed out of harm's way and yanked his sweatshirt and undershirt off before giving his jeans the same brusque treatment. He shoved Klaus up the bed so he lay amongst the pillows. They were both breathing heavily when Diego lay across him, bringing Klaus' long legs up and around his waist.

"Hands up," Diego growled, reaching behind him for the knife again. Klaus' eyes widened, and for once he didn't sass the hell out of him. Instead, he obeyed, bringing his hands up to grasp the head of the bed. "And don't move." Klaus nodded breathlessly.

Diego gave him a soft kiss, the contrast stark given the urgency of before. He quickly slicked himself with more lube and pressed into Klaus with what he hoped was surprising gentleness. And then he brought the knife up to rest against Klaus' throat. Klaus swallowed, eyes wider still, squeezing tight around him. It took all of Diego's willpower not to let his eyes roll back at the sensation.

Diego studied him for a moment, looking for any sign at all that this might not be okay. He only saw lust, and he grinned wolfishly. Klaus saw it and grinned back. Diego rewarded him with a thrust that made him gasp.

And then it was on again. The cuts on Klaus' collarbones had stopped bleeding. His arms were going the same way, but with the hand that wasn't holding a knife at Klaus' throat, Diegi pressed down on the skin beside it, reopening the wounds just slightly. Klaus cried out, clenching around him. Diego needed to take some deep breaths after that, worried he'd blow his load way too soon. He wanted this to last, wanted to taste it long after it had finished.

As he fucked Klaus to within an inch of his life, Diego kept the knife gently pressed against Klaus' throat. He was sure to not break skin, keeping his finger positioned so that the knife would cut him before it could cut Klaus. But Klaus didn't know that; he would only be able to feel the cool metal, the threat of the blade on his skin. Each time it touched him he tightened around Diego, making him wild with lust and need.

And still, Klaus remained his perfect good boy, not moving his arms from above his head. It was possibly the first time Diego had ever seen Klaus so unrepentantly obedient. He told Klaus this between thrusts, enjoying the little whimpers that escaped him.

"And next time," Diego murmured against Klaus' ear, slowing his thrusts, doing his damned best to draw this out for as long as possible. "I'm going to fuck you from behind, keep you nice and close, and keep this knife even closer to your throat. How's that sound, baby boy?"

Klaus whined, breathing as hard as if he'd run a mile. "Fuck, please, Diego," he bit out, head falling back amongst the pillows.

Diego grinned as he leant back and rolled his hips in a sensuous move that he knew drove Klaus mad before thrusting in hard again. Klaus wailed. Diego pushed Klaus' hips up higher, all but bending him in half, before he reached up and pressed three fingers into Klaus' mouth, holding him where he wanted.

"Tasting," Klaus managed to say around his fingers, "my own blood shouldn't be so hot!" He sounded upset at this realisation and Diego couldn't help but laugh. He'd forgotten about the dried blood on his hand until then, but enjoyed seeing his fingers in Klaus' mouth as they made him drool and gag just a little.

The sounds Klaus made got higher with every thrust now, and Diego knew he'd have to withdraw his fingers or the knife soon so he could jerk Klaus off. It was bordering on cruel how long he'd dragged this out, making Klaus as desperate as he was. But nobody had ever accused Diego of _not_ being a cruel bastard. In fact, Klaus regularly told him that he was, usually when Diego was doing something like this and turning Klaus into a whimpering, slobbering mess. Oh god, were those tears leaking out of his eyes? Fuck, _fuck_ , that was another thing Diego had been progressively learning shouldn't be hot to him, but absolutely was.

Klaus' sounds increased in volume and his back arched. His neck was dangerously close to the knife, knuckles white as he gripped the bedhead and came untouched. He tightened impossibly around Diego, clenching and writhing. Diego only had a few moments to marvel at the fact that _Klaus had fucking come untouched_ before he met his own end, whiting at the sides of his vision.

Diego was trembling, sweat pouring off of him, heart racing a mile a minute. He let the hand at Klaus' neck fall to the side and dropped the knife well out of Klaus' range as he propped himself up. He withdrew his other hand from Klaus' mouth and wiped the drool and blood on the pillow beside his head. He'd roll off Klaus in a moment, he just… needed to find the strength. It was harder than it looked.

"Jesus Christ," Klaus whispered, staring up at him with wide eyes before he let them close, exhaling shakily. The legs still wrapped around Diego's hips dropped. Diego took a moment to just stare down at the man below him. He was drenched in sweat, eyes leaking, drool and traces of blood over his face, far more than just traces of blood across his chest and arms. Diego finally managed to pull out of Klaus, earning him a final, tiny cry, before letting himself collapse onto Klaus' left side.

Klaus didn't cuddle into him, just kept staring blankly at the ceiling. Diego curled around him, hoping that Klaus just needed to catch his breath and that Diego hadn't actually gone too far this time. It was bound to happen one day, particularly given the way they liked to play on the edge, and Diego suddenly felt sick that today might be that day.

Fortunately, Klaus seemed to start breathing again and nuzzled into Diego, hissing when the movement seemed to pull at the injured parts of him.

"You okay?" Diego asked, pressing a soft kiss above Klaus' ear.

Klaus nodded. "Yeah, just. Mind. Kinda blown." He gestured vaguely over his head.

Diego huffed a laugh. "Do you want to just lay there for a bit?"

Klaus' eyes closed as he nodded. "Don't think you can pry me from here any time soon."

"Wouldn't dream of it."

*

By the time Diego made it over to the sink across the room, he was trembling violently. He knew the symptoms of adrenaline for what they were and they didn't really bother him. It was _strange_ that he was responding this way, but still something he knew how to handle. He'd been through more adrenaline-inducing things than this before, even recently, but he'd been fine. This? Was new.

He ran the tap until the water was warm, wetting some paper towels and another small towel that had increasingly been used to mop up after sex. On the way back to the bed he grabbed his first aid kit too. Klaus was still laying there, watching him through lidded eyes.

"You know what," Klaus mumbled, "I think just this once I'm going to accept aftercare."

Diego grinned and wiped the come off of Klaus' stomach before it had time to get dry and tacky. With that done, he began to gently mop at the dried blood on Klaus' chest. As he'd expected, the marks weren't deep and were all perfectly parallel. They'd been deep enough to draw a good amount of blood, but not bad enough that he'd even need butterfly stitches. Nothing even close. Diego was happy with his handiwork.

Klaus watched his hands as he worked, still lying there like it was all he could do. He didn't hiss as Diego started to gently blot at the wound with antiseptic. His eyes found Diego's and he gave him a soft smile as they shared a look.

Diego returned it, feeling his cheeks flame. He hurriedly returned his attention to tending the wounds, smoothing a small bandage over the cuts on Klaus' collarbones. All of the wounds would heal perfectly well without coverings, but there was something soothing about the act for Diego. It was the act of putting Klaus back together, even after taking him apart. In doing so, he felt like he was putting the parts of himself back into place too.

Sometimes, after they did things like this, Diego felt like his nerves were exposed, that he was so very raw. Klaus was often fine, but Diego would feel vulnerable and open in ways he didn't know how to process. There were only two things Diego knew how to do in those moments: flee or take care of Klaus. It seemed to be a dick move to flee after making Klaus cry before and/or during his orgasm, so Diego went with the next best thing and took care of him, even when Klaus insisted he didn't need it. Diego _liked_ taking care of Klaus, in the same ways that he liked calling him sweet names like 'baby boy' and giving him proper food and making sure he got something that resembled sleep. It filled his chest with a liquid warmth that couldn't be tempered. Taking care of him like this made him feel warm, like he was doing the right thing, even if Klaus sometimes protested it.

"Hey," Klaus started, voice a little croaky and rough from their earlier activities.

"I don't wanna hear it," Diego said flatly, pressing the next bandage down over the other side of Klaus' chest.

Klaus pouted. "You don't even know what I was going to say."

Diego sighed and raised an eyebrow at Klaus as he began to wipe the dried blood off of his neck. He was fairly certain that he hadn't so much as nicked Klaus but he wanted to be sure.

"It better not be anything like 'I don't need you to take care of me, Diego, I'm fine'," Diego cautioned.

"Hey, my voice does _not_ sound like that! And besides, it wasn't." He went to huffily cross his arms over his chest before wincing and remembering that Diego still hadn't tended to that series of wounds yet.

"Fine," Diego huffed, smoothing the bandage down even though it didn't need it. He just liked touching Klaus with gentleness, particularly when there had been far less of it earlier.

"You know I love you, right?" Klaus asked.

Diego snorted. That was how he started most of his requests to Diego. "What more do you want? I just blew your mind, baby boy."

"No, no, I don't want anything."

Diego raised an eyebrow.

"No, really. I just. I love you." Klaus was staring at him with a horribly sincere expression. Diego almost believed him. That wasn't the kind of face Klaus usually pulled before asking for a favour. He rested a hand on Diego's forearm, as if that might somehow convey more truthfulness behind his words.

Diego's stomach swooped. They hadn't used those words yet, not outside of, say, Klaus' wheedling and begging for favours. They'd used them as brothers but not as lovers. Unless, that was what Klaus meant—maybe he meant as brothers right now. For Diego, the words meant so much more now, and it was only a matter of time before the words slipped out of him. Until then he was holding onto them with an iron grip.

Klaus was still watching him. Shit.

"You're just saying that because you're drunk off endorphins," Diego chuckled, grateful that he was able to hide the tremor that threatened to show in his voice.

Klaus gave him a wry grin. "I'm not. Well, I mean, yes, I am drunk off endorphins, but that's not why I'm saying it. I'm saying it because it's true."

Diego swallowed. He sounded serious. Did it matter if he was drunk off endorphins? Would Klaus feel the same way in the morning? Would it matter if Diego said it back?

He'd always been a punch first, ask questions later kind of guy. Was this really any different?

"Yeah, well, see how you feel in the morning," he grumbled, pulling a different set of bandages out for the cuts on Klaus' arm. "But, for what it's worth," he said lightly, trying very, _very_ hard to picture the words in his mind, trying to put more focus on the tape than on catching glimpses of Klaus' face (he was relatively unsuccessful there), "I love you too."

Klaus positively beamed at him. "I can tell you as many times as you need to hear it."

Diego rolled his eyes but grinned despite himself. He felt weirdly lighter, like a weight had been lifted. Klaus… Klaus maybe loved him. He'd see in the morning how well that stuck. But for now? Klaus loved him.

"I should have made you shower before I did that," Diego realised with a frown at the bandages he'd so lovingly applied.

"It's okay," Klaus reassured him, patting his forearm where his hand still rested. "You can just put them on again after we've showered. I like the attention."

"You _always_ have my attention."

"I know, I love it."

Diego rolled his eyes and smiled despite himself before packing the small first-aid kit away. When it was zipped up, Klaus finally sat up, shifting so that he was closer to Diego. He winced slightly as he raised his arms to wrap around Diego's shoulders, bringing their foreheads together. Green eyes met his, big and imploring.

"Thank you," Klaus whispered, brushing their noses together.

Diego's heart fluttered a little. "Anytime, baby. Anytime you need, okay?"

Klaus' eyes went limpid at the nickname and he nodded.

"C'mon, let's get you showered and I'll play doctor with you again."

Klaus brightened. And Diego's heart raced just a little faster.

**Author's Note:**

> Whoo boy, Klaus nearly called Diego Daddy about 10 times in this. It was NOT that kind of fic, guys!! [But it's nearly happened in all 3 of my fics, so… I guess that's gotta happen, hey?]
> 
> ....Yeah okay, I'mma write Daddy kink now........
> 
> Also. I totally headcanon as Diego being just... [not so] secretly soft for Klaus. And just a massive service top for his baby. And just like, a lowkey accidental Daddy because he just loves taking care of Klaus in all of the ways he knows how. (: I have a lot of thoughts and feelings about these two :')))))
> 
> Thanks for reading!
> 
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